JPH06341527A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the occurrence of shift quality, and concurrently enhance durability by surely judging a tie-up in a clutch-to-clutch transmission section at an early stage, applying a correction signal to a hydraulic control means in such a way that overlapping of torques in charge of respective friction engagement means is lessened, and thereby making correction. CONSTITUTION:The automatic transmission for five forward speeds and reverse, which is equipped with a torque converter 111, and an main and an auxiliary transmission 112 and 113, is formed into a clutch-to-clutch transmission section for a brake B2 and a brake B3 wherein speed change for second speed and third speed is actuated. The engagement/disengagement of each friction engagement means is executed by controlling a hydraulic control means 20 based on the command from a computer 30, to which output signals from various sensor groups 40 are inputted. In this case, time from torque phase starting to inertia phase starting is detected by the computer 30 at the time of gear shift actuation, if the detected time is longer than the time of a specified torque phase, it is judged a tie-up, and a correction signal is outputted to a hydraulic pressure control circuit 20 so that overlapping of torques in charge of the respective friction engagement means is lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission which executes clutch-to-clutch shifts relating to two friction engagement devices.

[0002]

2. Description of the Related Art When performing a specific shift of an automatic transmission, it is often necessary to simultaneously engage and disengage two friction engagement devices (including a clutch and a brake in a broad sense). So-called clutch to clutch shift).
In this case, if the engagement and disengagement of the friction engagement devices are not properly synchronized, the output shaft torque will drop or the engine will blow up.

For this reason, conventionally, in order to perform such control, a one-way clutch having a function substantially equivalent to that of one friction engagement device is generally provided so that such a problem does not occur. Was considered.

However, in the method of synchronizing the friction engagement devices by using the one-way clutch in this way, the cost increases due to the attachment of the one-way clutch.
In addition, there are problems such as an increase in weight and an occupied space.

In view of such a point, in recent years, against the background of improvements in various sensor technologies and in electronic control technologies for hydraulic control devices, "clutch-to-clutch shift" can be directly executed without using a one-way clutch. Attempts to do so have become active again.

However, since this clutch-to-clutch shift is required to be optimized in a so-called torque phase region in which the rotational speed of the rotary member generally does not change, for example, a rotary sensor of the rotary member or Even in recent electronically controlled automatic transmissions equipped with an electric actuator and capable of controlling the above-described change mode by a computer, it is difficult to recognize that the mode is inappropriate, and therefore correction cannot be performed well. is the current situation.

In Japanese Patent Laid-Open No. 2-37128,
In view of such a current situation, the engine rotation speed during the shift operation is monitored, and when the engine rotation speed rises (when the engine rotation speed rises), the friction engagement devices are in the underlap state. (The engagement was relatively delayed with respect to the release), while each friction engagement device entered the overlap state when the engine speed decreased (for the release). Then, the engagement has become relatively premature: this state will be referred to as a tie-up state hereinafter).

[0008]

However, in such a determination method, although engine blowing can be detected relatively easily, tie-up determination is
The problem still remains that only a very long (or strong) tie-up can be determined, that is, the determination accuracy is extremely poor, and therefore a sufficiently effective hydraulic pressure correction control cannot be executed.

As described above, when the engagement side of the friction engagement device is too early (the tie-up occurs) relative to the release side of the friction engagement device, the output shaft torque sharply drops, and a strong shift shock occurs. In some cases, a very large load torque is applied to each member of the automatic transmission, which causes a decrease in durability.

The present invention has been made in view of such a conventional problem, and determines the tie-up in the clutch-to-clutch shift early and accurately, and executes effective hydraulic pressure correction control as a result. The purpose of the present invention is to reduce gear shift shock, prevent excessive load torque from being applied to each member of the automatic transmission, and further improve durability.

[0011]

The invention according to claim 1 is based on FIG.
As shown in (A), in a shift control device for an automatic transmission that executes clutch-to-clutch shift related to two friction engagement devices, engagement and release of the two friction engagement devices are controlled. The hydraulic control means, the means for detecting the time from the start of the torque phase to the start of the inertia phase during the gear shift operation, and the friction engagement device on the release side and the friction engagement device on the engagement side depending on the detected time. The above problem is solved by providing a means for giving a correction signal to the hydraulic pressure control means so as to correct the overlapping of the torques to be held.

Further, the invention of claim 2 is, in the shift control device of an automatic transmission for executing clutch-to-clutch shift relating to two friction engagement devices, as shown in FIG. 1 (B). The hydraulic control means for controlling the engagement and release of the two friction engagement devices, the means for detecting the time from the shift output to the start of the inertia phase, and the friction engagement device on the release side depending on the detected time. The problem is solved by providing a means for giving a correction signal to the hydraulic pressure control means so as to correct the overlapping manner of the holding torques of the mating side frictional engagement devices.

[0013]

In the tie-up state, the time of the torque phase (the time from the start of the torque phase to the start of the inertia phase) becomes longer than that in the good gear shift state. Focusing on this, in the present invention, the time of the torque phase is detected. For example, when it is longer than the time of the torque phase in a good gear shift state, it is determined to be tie-up, and the torque held by each friction engagement device is determined. A correction signal is given to the hydraulic control means so as to reduce the overlap, and the engagement and release timings are corrected.

Since the time from the shift output to the start of the inertia phase tends to be long in the tie-up state,
Even if the overlapping manner is corrected depending on this, the same effect can be obtained.

The "torque phase" referred to here is a state in which there is no change in the rotational speed for changing gears (for changing the gear ratio), that is, the input / output rotation of the automatic transmission is the gear. In the condition (torque phase in a broad sense) uniformly regulated by the ratio, in particular, even though the force balance of each rotating member is broken (to change the gear ratio), It refers to the state (torque phase in a narrow sense) where the actual rotation speed has not changed.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, a concrete example of an automatic transmission to which the present invention is applied is shown in a skeleton in FIG. The automatic transmission 2 includes a torque converter 111, a sub transmission unit 112, and a main transmission unit 113.

The torque converter 111 has a lockup clutch 124. The lockup clutch 124 is provided between a front cover 127 that is integrated with the pump impeller 126 and a member (hub) 129 to which a turbine runner 128 is integrally attached.

The crankshaft (not shown) of the engine 1 is connected to the front cover 127. The input shaft 130 connected to the turbine runner 128 includes an overdrive planetary gear mechanism 13 that constitutes the auxiliary transmission unit 112.
It is connected to one carrier 132.

A clutch C0 and a one-way clutch F0 are provided between the carrier 132 and the sun gear 133 in the planetary gear mechanism 131. The one-way clutch F0 is adapted to be engaged when the sun gear 133 makes a positive rotation relative to the carrier 132 (rotation in the rotation direction of the input shaft 130).

On the other hand, a brake B0 for selectively stopping the rotation of the sun gear 133 is provided. Further, a ring gear 134 which is an output element of the auxiliary transmission section 112 is connected to an intermediate shaft 135 which is an input element of the main transmission section 113.

The sub-transmission unit 112, when the clutch C0 or the one-way clutch F0 is engaged, has the planetary gear mechanism 1.
Since the whole 31 rotates integrally, the intermediate shaft 135
Rotates at the same speed as the input shaft 130. Further, in the state where the brake B0 is engaged and the rotation of the sun gear 133 is stopped, the ring gear 134 is accelerated with respect to the input shaft 130 and rotates normally. That is, the subtransmission unit 112 can set switching between high and low.

The main transmission unit 113 has three sets of planetary gear mechanisms 140, 150, 160, and these gear mechanisms 140, 150, 160 are connected as follows.

That is, the sun gear 141 of the first planetary gear mechanism 140 and the sun gear 151 of the second planetary gear mechanism 150 are integrally connected to each other, and the ring gear 143 of the first planetary gear mechanism 140 and the second planetary gear mechanism 150 are connected. Carrier 1
52 and the carrier 162 of the third planetary gear mechanism 160 are connected together. Further, the output shaft 170 is connected to the carrier 162 of the third planetary gear mechanism 160. Further, the ring gear 153 of the second planetary gear mechanism 150 is connected to the sun gear 161 of the third planetary gear mechanism 160.

In the gear train of the main transmission unit 113, it is possible to set one reverse gear and four forward gears, and a clutch and a brake therefor are provided as follows.

That is, the ring gear 153 of the second planetary gear mechanism 150 and the sun gear 161 of the third planetary gear mechanism 160.
A clutch C1 is provided between the intermediate shaft 135 and the intermediate shaft 135, and a clutch C2 is provided between the sun gear 141 of the first planetary gear mechanism 140 and the sun gear 151 of the second planetary gear mechanism 150 and the intermediate shaft 135.

A brake B1 for stopping the rotation of the sun gears 141 and 151 of the first planetary gear mechanism 140 and the second planetary gear mechanism 150 is arranged. Also, these sun gear 1
A one-way clutch F1 and a brake B2 are arranged in series between 41 and 151 and the casing 171.
The one-way clutch F1 is adapted to be engaged when the sun gears 141, 151 try to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 135).

The carrier 142 of the first planetary gear mechanism 140
A brake B3 is provided between the casing and the casing 171. In addition, the ring gear 16 of the third planetary gear mechanism 160
A brake B4 and a one-way clutch F2 as elements for stopping the rotation of No. 3 are arranged in parallel with each other between the casing 171. The one-way clutch F2 is adapted to be engaged when the ring gear 163 tries to rotate in the reverse direction.

In the automatic transmission 2 described above, it is possible to carry out a shift of one reverse speed and five forward speeds as a whole. FIG. 3 shows an engagement operation table of each clutch and brake for setting these shift speeds. In addition, in FIG. 3, a circle mark indicates an engaged state,
● indicates the engaged state when the engine is braked, and the blank indicates the released state.

As is apparent from this figure, the shift between the second speed and the third speed is the clutch-to-clutch shift of the brake B2 and the brake B3.

Engagement or disengagement of each clutch and brake is executed by driving an electromagnetic valve or a linear solenoid in a hydraulic control device (hydraulic control means) 20 based on a command from a computer 30. The computer 30 includes signals from various sensor groups 40, for example, a vehicle speed signal from a vehicle speed sensor 41 (a signal indicating an output shaft rotation speed N0), a throttle opening signal (accelerator opening signal) from a throttle sensor 42, and a pattern select switch. 43
Other basic signals such as a pattern select signal from the driver (a signal selected by the driver for driving with emphasis on power, driving with emphasis on fuel consumption, etc.), a shift position signal from the shift position switch 44, and a foot brake signal from the brake switch 45. , C0 sensor 46 receives the rotational speed signal of the clutch C0. The rotation speed of the clutch C0 is the second
Since the turbine rotation speed (the input shaft rotation speed of the automatic transmission) Nt is the same during the shift between the third speed and the third speed, the turbine rotation speed Nt should be known by detecting the rotation speed of the clutch C0. You can

Various methods have been conventionally known for the hydraulic control itself when shifting the brakes B2 and B3, so a detailed description thereof will be omitted here, but basically, both the brakes B2 and B3 are The back pressure of the accumulator provided in the oil passage may be controlled by the actuator control valve and the linear solenoid that controls the actuator control valve. On the release side, since the control is to reduce the hydraulic pressure, the drain amount of the hydraulic circuit may be controlled by a linear solenoid.

Next, FIG. 4 shows a control flow executed by the computer.

In this embodiment, from the second gear to the third gear.
The present invention is applied when upshifting to the speed stage.

As is apparent from FIG. 3, the upshift from the second speed to the third speed is a clutch-to-clutch shift by releasing the brake B3 and engaging the brake B2. In this embodiment, the engagement of the brake B2 is executed in a predetermined procedure, and when the tie-up is determined, the drain speed of the release hydraulic pressure of the brake B3 is controlled to be relatively faster. I am trying to eliminate the tie-up. The release hydraulic pressure of the brake B3 increases when the duty ratio Dsln of a linear solenoid (not shown) increases and decreases when it decreases.

First, in step S201, it is determined whether or not there is an upshift output from the second speed stage to the third speed stage. When there is an upshift output, a shift valve (not shown) is switched by a solenoid valve driven by a command from the computer 30, and basically the brake B3
Is released and the brake B2 is engaged. As a result, the movement of the oil is started. In this embodiment, however, the relative transient characteristics of the movement of the oil, that is, the decrease of the hydraulic pressure of the brake B3 and the increase of the hydraulic pressure of the brake B2 (steps of overlapping of the torques to be undertaken) in this step and subsequent steps ) Is properly controlled.

If the determination in step 201 is YES, steps 202 to 204 determine the avoidance condition for the hydraulic pressure correction during tie-up. Here, in step 202, the shift is due to the fact that the current running state crosses the upshift shift line from the second speed stage to the third speed stage from the map of the throttle opening and the vehicle speed (automatic shift instead of manual shift). It is determined in step 203 whether or not the oil temperature exceeds a certain value (not in shift at extremely low temperature), and in step 204, a linear solenoid for operating the brake B3. It is determined whether or not the SLU fail determination is none. Steps 201-20
If any of the determinations in 4 is NO, the process is reset as it is and the control according to the present invention is not particularly executed.

If both judgments are YES, it is judged at step 205 whether or not the torque phase in the narrow sense has started. The start of the torque phase is judged by detecting a slight decrease in the differential value of the output shaft rotation speed N0. If it is not determined that the torque phase has started, it is reset.

If it is determined that the torque phase has started, it is determined in step 206 whether the flag F = 0 or not, and the flag F =
If 0, the timer T is zero-started in step 206, and the flag F = 1 is set in step 208. And
The time elapsed from the start of the torque phase is measured until the start of the inertia phase is detected in step 209.

Here, the start of the inertia phase is detected by the change of the turbine rotation speed Nt. When it is determined that the inertia phase has started, the determination in step 209 becomes YES, and it is determined in step 210 whether or not there is a throttle change above a certain level during gear shifting as a hydraulic pressure correction avoidance condition.
When it is O, it is reset to avoid correction. In the case of YES, it is determined in step 211 whether the time T from the start of the counted torque phase to the start of the inertia phase, that is, the torque phase time T exceeds a predetermined time τ. In the case of YES, it is determined that tie-up has occurred, and in step 212, the duty ratio Dslu of the linear solenoid is Δ in order to reduce the hydraulic pressure of the brake B3 (during the next shift).
The oil pressure is corrected so as to reduce only Dslu.

As a result, the tie-up is eliminated from the next shift. Here, the value of τ is the time of the torque phase when a favorable gear shift is performed, and tie-up is determined based on this. If the determination in step 211 is NO, the tie-up is not determined, so the hydraulic pressure correction is not performed.

In this control flow, a step for judging whether the torque phase time T is longer than the guard timer T0 (T0> τ) is additionally provided. When T> T0, it is considered that the tie-up is very strong. (Not the next shift)
The B3 hydraulic pressure may be reduced in real time during the shift.

Next, FIG. 5 shows a shift transient characteristic when this control flow is executed.

The broken line in the figure shows the characteristic when tie-up occurs, and the solid line shows the characteristic when correction is made when tie-up is detected in the control flow.

The differential value of the output shaft rotation speed N0 (acceleration of output shaft rotation) shows a characteristic substantially similar to the output shaft torque T0. In the case of the broken line, the time from the torque phase to the start of the inertia phase becomes long, and it is determined to be tie-up. In this case, at the time of the next shift, the duty ratio Dslu of the linear solenoid for controlling the engagement pressure of the brake B3 is corrected so as to decrease the hydraulic pressure of the brake B3 faster, so that a good shift characteristic (solid line) is obtained. Is something that can be done.

In the above embodiment, the tie-up determination is made based on whether the time from the start of the torque phase to the start of the inertia phase exceeds a predetermined time, but the time from the shift output to the start of the torque phase is almost the same. Since it is constant, the same effect can be obtained by measuring the time from the shift output to the start of the inertia phase.

Also, in this embodiment, the setting of the release pressure of the brake B3 is changed in the next shift, but the result is reflected in the shift in real time by the above-mentioned configuration, for example. You can also

[0048]

As described above, according to the present invention, the tie-up can be determined quickly and surely, so that the clutch-to-clutch shift can be controlled more appropriately. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a block diagram schematically showing an automatic transmission for a vehicle to which the present invention is applied.

FIG. 3 is a diagram showing an operating state of each friction engagement device of the automatic transmission.

FIG. 4 is a flowchart showing a control flow executed in a computer for controlling the automatic transmission.

FIG. 5 is a diagram showing a shift transient characteristic when the control flow is executed.

[Explanation of symbols]

 B2, B3 ... Brake (friction engagement device) 20 ... Hydraulic control device (hydraulic control means) 30 ... Computer 40 ... Various sensor parts

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunihiro Iwatsuki, Toyota city, Toyota city, Aichi prefecture, Toyota Motor Corporation (72) Inventor, Hiromichi Kimura, Toyota city, Aichi prefecture, Toyota city, Toyota city (72) Inventor Yasuo Hojo, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Atsushi Tabata, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Masahiko Ando, Aichi Aisin AW Co., Ltd., 10 Takane, Fujii-machi, Anjo, Aichi Prefecture (72) Inventor Akira Fukatsu Aisin AW Co., Ltd., 10 Takane, Fujii-cho, Anjo, Aichi Prefecture (72) Yoshihisa Yamamoto Aichi No. 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture

Claims (2)

[Claims] 1. A shift control device for an automatic transmission that executes clutch-to-clutch shift relating to two friction engagement devices, comprising: hydraulic control means for controlling engagement and disengagement of the two friction engagement devices; The means for detecting the time from the start of the torque phase to the start of the inertia phase during operation, and the way in which the holding torques of the disengagement side friction engagement device and the engagement side friction engagement device overlap depending on the detected time A shift control device for an automatic transmission, comprising: means for applying a correction signal to the hydraulic pressure control means so as to correct the shift. 2. A shift control device for an automatic transmission that executes clutch-to-clutch shift relating to two friction engagement devices, comprising: hydraulic control means for controlling engagement and disengagement of the two friction engagement devices; A means for detecting the time from the output to the start of the inertia phase, and the hydraulic pressure so as to correct the overlapping manner of the holding torques of the disengagement side friction engagement device and the engagement side friction engagement device depending on the detected time. A shift control device for an automatic transmission, comprising: a means for applying a correction signal to the control means.